1. Field of the Invention
The present invention relates to earth excavating equipment and particularly to machines for drilling holes into the earth. More particularly the invention concerns heavy duty mobile devices for drilling large holes such as six foot or larger diameter foundation holes which are relatively deep such as twenty feet or deeper holes.
2. Discussion of the Relevant Art
There are many types of drilling rigs available for drilling holes into the ground. Some of the commercially available drilling rigs are more useful than others. Some drilling rigs are designed primarily for one type of usage and are not very useful, or in some cases not useful at all, for other uses. For example, U.S. Pat. No. 4,645,084 discloses a device which will drill holes at a variety of angles, however the device as illustrated is mounted on a truck and is light weight and would not be suitable for drilling large diameter holes, or deep holes, or holes on a steeply inclined terrain.
U.S. Pat. No. 1,971,922 discloses a drilling apparatus that is suspended by cable from the end of a crane. The weight of the telescopic kelly sections, auger and electric motor used to drive the kelly sections assist in forcing the auger into the ground. Power downcrowding is not possible with this apparatus.
U.S. Pat. No. 4,199,033, which is hereby incorporated herein by reference, discloses a device which as illustrated, is mounted on the arm or boom of a backhoe. This device is shown drilling holes into the earth at a variety of angles. While this device appears to be capable of drilling medium diameter holes, it does not appear to be capable of drilling large diameter holes or relative deep holes at least without a great deal of difficulty. The device, however, can be power downcrowded by the boom of the backhoe; however, the movement would require complicated control of several hydraulic cylinders simultaneously even for vertical holes that would be difficult for the operator. Holes drilled at an angle would require even more complicated control to the degree that it would not appear to be practical to use this device for such excavations.
U.S. Pat. No. 2,910,274 discloses an expandable bucket device for digging bell-shaped holes for footings which is connected by cable to the end of the boom of a crane. Although this device appears to be capable of drilling relatively large diameter holes it appears that only vertically oriented holes are possible since the weight of the drill stem and excavating bucket appear to be the only force bearing on the bucket to drive the bucket into the ground. The device is limited in drilling depth by the length of a vertical column depending from the free end of the boom.
U.S. Pat. No. 4,627,499, which is hereby incorporated herein by reference, discloses perhaps a more useful drilling device for drilling foundation holes which is mounted on the end of a boom on a track type vehicle having a rotatable turnable. The drilling device is of the drill mast type and involves a single kelly bar driven by a final drive which is pivotally mounted to the boom at the bottom of the drill mast. While the drilling rig disclosed in U.S. Pat. No. 4,627,499 is perhaps more useful than the others it is limited to a single kelly. The depth of the hole is therefore limited by the length of the kelly bar which is in turn limited by the height of the drill mast as are all drilling devices which use a drill mast of the type illustrated in the patent. Thus while relatively deep holes can be drilled with devices using a drilling mast to do so requires a long mast which limit the usefulness of such devices in environments which require a low overhead clearance.
U.S. Pat. No. 3,216,511, which is hereby incorporated herein by reference, discloses a crawler type vehicle having tracks, a turntable and boom having a distal end.
What is needed is a heavy duty augering apparatus which can be power downcrowded and can drill large diameter holes to great depths with relatively little overhead requirements. What would be even more useful would be for such an apparatus to be adaptable for mounting on a large variety of vehicles thereby producing a variety of drilling rigs. It would also be useful if such an augering apparatus could be tilted in all directions. It would be particularly useful if such an augering apparatus were mountable on the free end of a boom-containing vehicle.
It would be especially useful for such an augering apparatus to be adaptable to a vehicle having a telescopic boom, mounted on a turntable with crawler type tracks thereby forming a drilling rig that can be used on steeply inclined terrains, that can easily position the augering apparatus over a preselected drill site at any desired axial angle of orientation into the ground, that can reach over walls or other in-place large machines or other obstacles and drill holes without removing such things, and that can be used in environments with low overhead while still being capable of drilling large diameter holes to great depths. It would also be beneficial if such a drilling rig were readily transportable on a flat bed trailer with a total height that would allow it to pass underneath bridges and that when removed from the trailer would be in a state ready for immediate use without the need to assemble components together before the drilling rig can be used.